Green Roofs
Green roofing is an excellent means of improving the environmental profile of a structure while also greatly enhancing its aesthetics. The Utilihab platform supports both conventional green roof systems -which are walkable- and the use of the Green Wall panel system as previously mentioned in the section on exterior wall panel systems. In general, they are limited to use in combination with a membrane roof system, but the Green Wall panel does have the option of being mounted on ridged and even curved roofs where there is no walking deck. The basic form of green roof system used with Utilihab employs a corrugated plastic interlocking drainage plate or mat system relying on gravity and raised perimeter tie beams to keep it in place. Systems often include modular plastic soil containment edging systems to accommodate walkways and deckings but this can also often be accommodated simply with conventional plastic garden edging. The drainage plates are covered with a geotextile or other filter/root barrier sheeting and a light growing medium is placed on top, optionally with an additional cover material to prevent being picked up by wind before plant growth is well established. Drip irrigation systems are commonly installed with these. These systems can support from 5cm (‘extensive’ systems supporting grasses and low moisture plants) to 1m (intensive systems supporting shrubs and small trees) of soil and so can add substantially to the roof load of a structure. This must be taken into account when choosing the basic Utilihab Primary frame bay span and roof joists. Generally, this form of green roof cannot be used on cantilevered roof overhands. Container gardening is accommodated simply by integrating suitable plant containers with a roof decking system. Containers can simply be free-standing -usually on a foam pad to prevent roof membrane tears- with decking installed around them or the containers can be mechanically integrated to the decking itself. Ponds and pools can also be accommodated by such containers. The standard Utilihab deck framing allows for the creation of many kinds of planters/containers based on T-slot profile framing. As will be discussed in another section, very sophisticated automated hydroponics can be accommodated with this. But the more practical for green roof applications are simple single-piece rotomolded polyethylene containers equipped as sub-irrigation planters that have flanges for bolting to the deck frame or can be framed-around with planking complimenting the deck planking. A simple enclosure of four profile posts and a top frame covered by polywood planking attached by snap-lock strips to the profile frame can produce a very attractive planter structure suited to an infinite variety of designs. The Green Wall system offers the lightest of green roof options and is the one form that can support placement on ridged roofs and cantilevered roof overhangs as well as placement on top of panelized roof systems rather than membrane roofing. Green Wall panels are simple plastic panels with a polymeride felt layer as a growing medium and integral drip irrigation tubing. They are mounted in largely the same fashion as solar panels, bolting directly to a deck frame grid like surface-mounted fitted wall panels or onto support battens. Their drip irrigation tubing is then plugged into a supply network behind the sets of panels. Flat roof forms will usually employ some small drainage perforations in the plastic back-panel and perimeter trim to prevent downing of the plants by rain. Since nutrients are added to supply fluid for these panels, they are not normally used In combination with a rainwater catchment. These panels do not provide a walkable surface and are limited to lighter low-profile plants.